The invention relates to a completion valve assembly for use in a subterranean well.
In a subterranean well, a packer may be used to form a seal between the outside of a tubing (a production tubing, for example) and the inside of a well casing. This seal may be useful for testing or production purposes to ensure that well fluid below the packer travels through a central passageway of the tubing.
The packer typically includes a resilient elastomer member that surrounds the tubing. When the packer is set, compression sleeves of the packer compress the member to cause the member to radially expand between the tubing and the well casing to form the seal. For purposes of maintaining compression on the member, stingers of the packer typically extend in a radially outward direction when the packer is set to grasp the well casing to lock the positions of the compression sleeves.
To establish the force that is necessary to set the packer, two techniques are commonly used. A weight set packer uses the weight of a tubular string that is located above the packer and possibly the weight of associated weight collars to derive a force that is sufficient to compress the elastomer member to set the packer.
In contrast to the weight set packer, a hydraulically set packer uses a pressure differential that exists between the fluids of the central passageway of the tubing and the annular region outside of the tubing (called the xe2x80x9cannulusxe2x80x9d) to establish a force that is sufficient to set the packer. More specifically, the hydraulically set packer typically is set by pressurizing fluid that is present in the central passageway of the tubing. However, before this pressurization occurs, the tubing must be sealed, a requirement that means the central passageway of the tubing must be sealed off below the packer for purposes of forming a column of fluid inside the tubing that can be pressurized. The seal may be formed by a plug.
In addition to using the plug to set a hydraulically set packer, plugs may be used for other downhole purposes, such as pressure testing the tubing. If pressure testing is conducted, it is important to ensure that none of the downhole tools, including any hydraulically set packers, are prematurely activated by the pressure testing.
After the hydraulically set packer is set, the plug may be removed by running a tool downhole to remove the plug or by pressurizing the interior of the tubing to a level that is sufficient to dislodge the plug from the bottom of the tubing. A wireline or slickline run is risky, particularly in deep water or sea water wells. Also, the rig time is expensive when two runs are required. Thus, interventionless operation is desired.
For purposes of filling the tubing with a fluid, a fill tube may be placed in the central passageway. Another technique to fill the tubing uses a tubing fill valve. In this manner, the tubing fill valve controls fluid communication between the annulus and the central passageway of the tubing. Typically, the tubing fill valve is open when the tubing is run downhole for purposes of permitting a formation kill fluid (already present inside the casing) to fill the central passageway of the tubing in case the plug seals or valves leak. Because the hydraulically set packer is set in response to the pressure differential exceeding a predetermined differential threshold, it is possible for this threshold to be exceeded before the packer has reached the desired depth. Therefore, the packer may be unintentionally set at the wrong depth.
Thus, there is a continuing need for an arrangement that addresses one or more of the problems that are stated above.
In an embodiment of the invention, an apparatus for use in a subterranean well includes a tubular member, a hydraulically set packer, a control line and a valve. The tubular member has an internal passageway, and the hydraulically set packer circumscribes the tubular member and is adapted to be set in response to a difference between a first pressure that is exerted by a first fluid in a passageway of the tubular member and a second pressure that is exerted by a second fluid in an annular region that surrounds the packer. The control line is adapted to communicate an indication of the first pressure to the packer, and the valve is adapted to selectively block the communication of the indication to prevent unintentional setting of the packer.
In another embodiment of the invention, an apparatus for use with a subterranean well includes a tubular member and a valve. The tubular member has a longitudinal passageway and at least one port for establishing communication between the passageway and an annular region that surrounds the tubular member. The valve is adapted to open and close the port and lock the valve closed after the valve closes more than a predetermined number of times.
Advantages and other features of the invention will become apparent from the following description, drawing and claims.